A new study in the Journal of the American Medical Association suggests that a useful predictor of how long older adults live is how fast they walk. According to the report, people who walked 1 meter per second (about 2.25 mph) or faster consistently lived longer than others of their age and sex who walked more slowly.

Unfortunately, you can't reach a ripe old age by changing your walking speed. According to researcher Dr. Stephanie Studenski, a professor of medicine at the University of Pittsburgh:

"Your body chooses the walking speed that is best for you, and that is your speed, your health indicator," Studenski said. "And that's what it really is: an indicator. Going out and walking faster does not necessarily mean you will suddenly live longer. You still need to address the underlying health issues."